To the rational being only the irrational is unendurable, but the rational is endurable.
Τῷ λογικῷ ζώῳ μόνον ἀφόρητόν ἐστι τὸ ἄλογον, τὸ δ᾿ εὔλογον φορητόν.
Original text (Ancient Greek)
Variants
To a reasonable creature, that alone is insupportable which is unreasonable; but everything reasonable may be supported.